1. Field of the Invention
The present invention relates to a hermetically sealed container and an image forming apparatus using the hermetically sealed container.
2. Related Background Art
As a flat panel display, a vacuum fluorescent display utilizing a thermionic cathode, an image display utilizing cold cathodes such as a surface conduction electron emitting device, and the like are known.
Such flat panel image forming apparatuses are disclosed, for example, in Japanese Patent Application Laid-Open Nos. 10-236851, 10-188787, and the like. The schematic structure of such flat panel image forming apparatus is shown in FIG. 7. In FIG. 7, numeral 101 denotes a face plate (front substrate), 102 denotes a rear plate (back substrate), 103 denotes an outer frame, and a hermetically sealed container 7 is constituted by bonding the abutment portions of the components 101, 102, 103. In general, the abutment portions are bonded by adhesives such as a frit glass. Moreover, in the image forming apparatus shown in FIG. 7, electrons emitted from an electron source 109 are accelerated by an anode voltage applied to an image forming member 108 such as a phosphor, so that emission and display are performed.
FIG. 4 is a sectional view showing the basic constitution of the vacuum fluorescent display disclosed in the Japanese Patent Application Laid-Open No. 10-236851 among the above-described flat panel displays. In FIG. 4, numeral 14 denotes a front glass, 12 denotes a plate glass disposed opposite to the front glass, and 16 denotes a spacer glass disposed between two glasses at the peripheral edge of the front glass 14 and plate glass 12. These constitute a vacuum fluorescent display 10 as a hermetically sealed container.
In FIG. 4, character W denotes the width of the spacer glass 16, and T denotes thickness. Numeral 24 denotes a filament-like thermionic cathode which emits electrons, 30 denotes a phosphor layer which is irradiated with the electrons to obtain emission, and these components are disposed on the plate glass 12.
According to the present invention, there is provided a hermetically sealed container comprising: a front substrate; a back substrate disposed opposite to the front substrate; and an outer frame disposed between the front substrate and the back substrate. The front and back substrates, and the outer frame are bonded with an adhesive to form a hermetically sealed space. When a ratio W/T of the width W and thickness T of the outer frame is set to the aspect ratio A of the outer frame, 1.5xe2x89xa6A.
Moreover, according to the present invention, there is provided an image forming apparatus using a hermetically sealed container comprising: a front substrate having an image forming member and a conductive film; a back substrate disposed opposite to the front substrate and provided with an electron source; and an outer frame disposed between the front substrate and the back substrate. The front and back substrates, and the outer frame are bonded with an adhesive to form a hermetically sealed space. When a ratio W/T of the width W and thickness T of the outer frame is set to the aspect ratio A of the outer frame, 1.5xe2x89xa6A.
Furthermore, according to the present invention, when the ratio W/T of the width W and thickness T of the outer frame is set to the aspect ratio A of the outer frame, 1.5xe2x89xa6Axe2x89xa630.